I had the same problem on one site out of 15. Debugging indicated that was one plugin causing the issue. I did deactivate it and try – but was not resolved, until all plugins deactivated and turned on one by one. When I activated Quick Notice Bar Pro – issue with no popup for adding media returned.
Deactivated Quick Notice Bar Pro Version 2.0.3 | By Shaon – and all has been resolved.
This was one plugin that has caused me grief in the past as well.
I will look for alternate options. I have reported the issue to the developer and voted on www.remarpro.com.
